What are some reasons for swords in sci-fi.

Hard mode:
Don't mention Dune or keeping the inside of a ship safe since both have have easy workarounds.

One reason could be supersoldiers/soldiers in advanced armor fighting against hordes of weaker aliens.

A gun could only take out as many enemies as it has bullets. A strong sci-fi metal sword could keep hacking for days.

Another would be fighting on a far off world where resupply would be rare.

Swords would augment what you could bring and what you could make on the new planet.

Oh,one reason would be a planet/civilization where swords (like machetes) are useful tools (like many countries here).

And having them around means they're often pressed into other uses.